The nightingale catch quest starts when you put the cages into the bags of your horse at the position you put them in. On the map a marker is set. All three cages remain in the bags of the horse.
You have to drop them on the ground one in each location of birds sound
I know. I just didn’t want to start the quest. I just wanted more space inside my inventory and put them into the horses bags. At the moment I put them in, the quest starts and a marker is placed on the horses position. I don’t think that behavior is intended…
Ahhhhhh, yeah i noticed that while doing the quest, because instead of drooping them i accidentally moved to horse